Buildings have been constructed from logs for hundreds of years. Some of these buildings have employed rough logs with the bark still on them. The ends are notched so that one wall joins an adjacent wall at a right angle, and the notches cooperate to lock the two walls together.
By connecting the ends of four such walls together at their adjacent corners a four sided building is constructed. The gaps between adjacent lower and upper logs are filled with material such as wet clay and straw or other fibers. The clay hardens as it dries and forms relatively air tight connections between two logs. However, over time the logs tend to dry and shrink and the bark tends to crumble. As a result the clay cracks, breaks and crumbles. Replacement of the caulking clay or similar material becomes a frequent maintenance requirement.
Bark is generally removed from logs in more recent years to avoid problems associated with bark deterioration. Removal of bark reduces insect problems and reduces problems relating to drying of logs and to shrinkage. However, the problems relating sealing the spaces between upper and lower logs remains.
Builders of some log buildings have chipped wood away to form each log into a beam with a square cross section. Chipping away portions of a log is a labor intensive activity that requires great strength, endurance and time. This system reduces the size of cracks between adjacent logs. However, these cracks must still be sealed to keep water out and reduce the passage of air. Some settling between such beams occurs due to changes in moisture content of the wood and deterioration of the rough outside surfaces.
Logs are shaped by powered cutters to have uniform diameters from one end to the other to make log buildings today. Engaging edges of the logs are also shaped to obtain substantiality air tight mounting surfaces that will shed water. These logs will still dry, warp and settle some over time.
Connections between logs at the corners of walls require hand fitting of the logs. Even with power tools, cutting notches into the sides of logs is a time consuming task. Cutting notches in logs for floor joist as well as for rafters is also a time consuming task. When using notches in two logs to form a right angle connection between the two logs, a substantial amount of wood is removed to form the required joint. The removal reduces the strength of the logs at the connection location. If a notch is cut half way through a floor joist or rafter and a mating notch is cut in a supporting log, the strength of each log may be reduced by half or more. This is a particularly serious problem for floor joists and rafters which are often required to support significant loads.